Colombo weather in May

In May, Colombo sees average daytime highs of 30°C and overnight lows near 27°C, with 279 mm of rain across 28.9 wet days and about 12.3 hours of daylight. It is the 5th-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 30°C through the month. The sky is clear or mostly clear about 5% of the time in May, and the air most often feels miserable.

Daylight stretches from about 12 h 12 min at the start of May to 12 h 24 min by month's end. Set against the rest of the year, May is Colombo's 8th-clearest and 5th-windiest month. For the whole year in context, see Colombo's year-round climate.

Daytime high
30°
5th warmest
Overnight low
27°
12th coldest
Rainfall
279 mm
28.9 wet days
Daylight
12 h 18 min
5:57 AM – 6:16 PM
Cloud cover
79%
8th clearest
Wind
17 km/h
5th windiest
Solar energy
4.94 kWh/m²
Travel score
2.9
out of 10

Colombo is largest city and de facto capital of Sri Lanka.

Air quality
Elevated
PM2.5 23.6 µg/m³ · 2019

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 30°C through the month.

A typical May day in Colombo reaches about 30°C in the afternoon and slips back to 27°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 29°C and 30°C. Set against its neighbours, May runs on par with April and about 1°C warmer than June.

25°28°30°33°35°151015202531
Avg high (°C)Avg low (°C)
13027
23027
33027
43027
53027
63027
73027
83027
93027
103027
113027
123027
133027
143027
153027
163027
173027
183027
192927
202927
212927
222927
232927
242927
252927
262927
272927
282927
292927
302926
312926

How May really feels in Colombo

Once humidity and wind are folded in, May averages 31 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in May is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Colombo weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 24°537.911.65.3
Feb30° / 25°547.811.85.1
Mar30° / 26°7514.9124.3
Apr30° / 26°16624.812.13.2
May30° / 27°27928.912.32.9
Jun29° / 26°24326.812.43.2
Jul28° / 26°18324.412.43.7
Aug28° / 26°16823.712.23.9
Sep28° / 26°22324.5123.7
Oct29° / 25°3262611.83.5
Nov29° / 25°30723.711.73.6
Dec29° / 25°16415.911.64.6

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 5% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 16% of May, with mostly cloudy or overcast conditions the remaining 79%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12971
22971
32971
42872
52773
62674
72674
82674
92476
102476
112476
122377
132377
142278
152278
162179
172179
182080
192080
201981
211981
221882
231783
241783
251783
261684
271585
281486
291486
301486
311387

Chance of precipitation in May

Any precipitation

Colombo gets around 279 mm of rain over 28.9 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 93% and peaks near 95% on the wettest days.

0%20%40%60%80%100%151015202531
Rain chance (%)
190
291
391
491
591
691
792
892
992
1092
1192
1292
1392
1493
1593
1693
1793
1893
1993
2093
2194
2294
2394
2494
2594
2695
2795
2895
2995
3095
3195

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

Most of May feels miserable — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, May lands in the miserable band about 99% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
1298
2298
3298
4298
5298
6298
7298
8199
9199
10199
11199
12199
13199
14199
15199
16199
170100
180100
190100
200100
210100
220100
230100
24199
25199
26199
27199
28199
29199
30298
31298

Wind in May

Winds average 17 km/h in May.

Across May, daily wind ranges from about 12 km/h on the calmest days to 19 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202531
Wind speed (km/h)Feels
112light breeze
213light breeze
313light breeze
413light breeze
514light breeze
614light breeze
714light breeze
814light breeze
915light breeze
1015light breeze
1115light breeze
1216light breeze
1316light breeze
1416light breeze
1516light breeze
1617light breeze
1717light breeze
1817light breeze
1917light breeze
2018light breeze
2118light breeze
2218light breeze
2318light breeze
2418light breeze
2518light breeze
2619light breeze
2719light breeze
2819light breeze
2919light breeze
3019light breeze
3119light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 12 h 12 min at the start of May to 12 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 12 minutes over May. Sunrise moves from 6:01 AM to 5:57 AM, and sunset from 6:15 PM to 6:19 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.26:016:15
212.26:006:15
312.36:006:15
412.36:006:15
512.35:596:15
612.35:596:15
712.35:596:15
812.35:596:15
912.35:596:15
1012.35:586:16
1112.35:586:16
1212.35:586:16
1312.35:586:16
1412.35:586:16
1512.35:586:16
1612.35:576:16
1712.35:576:16
1812.35:576:17
1912.35:576:17
2012.35:576:17
2112.35:576:17
2212.35:576:17
2312.35:576:17
2412.35:576:18
2512.45:576:18
2612.45:576:18
2712.45:576:18
2812.45:576:18
2912.45:576:19
3012.45:576:19
3112.45:576:19

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 4.94 kWh/m².

For context, solar energy here swings from a low near 4.64 kWh/m² to a high of 6.31 kWh/m² in March across the year — May's 4.94 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.3Bright
45.3Bright
55.2Bright
65.2Bright
75.2Bright
85.1Bright
95.1Bright
105.1Bright
115.1Bright
125.0Bright
135.0Bright
145.0Bright
155.0Bright
165.0Bright
174.9Bright
184.9Bright
194.9Bright
204.9Bright
214.9Bright
224.8Bright
234.8Bright
244.8Bright
254.8Bright
264.8Bright
274.8Bright
284.8Bright
294.7Bright
304.7Bright
314.7Bright
Planning a trip in May

Hazard calendar for Colombo

In seasonPeak

In May, Colombo sits inside its cyclone season. The full year is below, with each hazard's peak months called out.

Colombo sits in the North Indian Ocean cyclone zone; the season peaks May and October–November.

Cyclone
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is May a good time to visit Colombo?

Our two travel scores rate May for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

2.9
Sightseeing
12th-best month of the year
3.9
Beach & pool
12th-best month of the year

May is a weaker month for outdoor sightseeing in Colombo.

What to pack for Colombo in May

From May's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In May, Colombo sees daytime highs around 30°C and nights near 27°C. Pack light clothes and rain gear. Worth having: sun protection. About 29 days see rain.

light clothesrain gearsun protection

Sea temperature near Colombo in May

The nearest coast averages about 29°C in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in April at about 30°C and coldest in August near 27°C.

The water stays above 20°C all year — warm enough for a swim any month.

26°28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan28Warm
Feb28Tropical
Mar29Tropical
Apr30Tropical
May29Tropical
Jun28Tropical
Jul28Warm
Aug27Warm
Sep28Warm
Oct28Tropical
Nov29Tropical
Dec28Tropical

UV index in Colombo in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Colombo peaks around September 10 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 10 (very high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highSep 10UV 13Dec 15UV 10
UV index (midday)Level
Jan10Extreme
Feb12Extreme
Mar12Extreme
Apr12Extreme
May12Extreme
Jun11Extreme
Jul11Extreme
Aug13Extreme
Sep13Extreme
Oct12Extreme
Nov10Extreme
Dec10Very high

Air quality in Colombo in May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May falls, not just the annual average.

Air quality in Colombo is worst in February — around 33 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (September, 16 µg/m³).

Seasonal pattern from CAMS reanalysis, scaled to Colombo's WHO annual average of 23.6 µg/m³.

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateFeb 1433 µg/m³Sep 1116 µg/m³
PM2.5 (µg/m³)Level
Jan32Moderate
Feb33Moderate
Mar32Moderate
Apr25Moderate
May21Moderate
Jun17Moderate
Jul16Moderate
Aug16Moderate
Sep16Moderate
Oct18Moderate
Nov27Moderate
Dec30Moderate
Location & terrain

Where is Colombo?

Colombo sits at 6.9°N, 79.8°E, 7 m above sea level, in Sri Lanka. The nearest listed city is Kolonnawa, 4.0 km away.

Topography around Colombo

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Colombo.

Within 3 km, the terrain around Colombo has only modest variations in elevation — a maximum elevation change of 32 m around an average of 5 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 71 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,145 m.

The land around Colombo is covered by artificial surfaces (45%) and water (38%) within 3 km, water (55%), artificial surfaces (22%) and trees (20%) within 16 km, and trees (59%) and water (37%) within 80 km.

3 km
32 m
16 km
71 m
80 km
2,145 m
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Kolonnawa 4.0 km · Peliyagoda 5.0 km · Kotikawatta 7.0 km · Hendala 7.0 km · Wattala 8.0 km · Pita Kotte 8.0 km · Kelaniya 8.0 km · Sri Jayewardenepura Kotte 9.0 km

Sri Lanka travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type D / G / M
230 V · 50 Hz
Prices
≈ 27% of US
price level, 2025
GDP per capita
$5,002
2025
Happiness
4.0 / 10
World Happiness, 2025
Safe drinking water
47%
of population, 2024
Homicide rate
3.3
per 100k, 2019
Road deaths
19.7
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 486
Religion
Buddhist 70%Hindu 13%Muslim 10%Roman Catholic 6%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Colombo (6.9355°, 79.8487°, elevation 7 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).